- •1.2 THEORETICAL INTRODUCTION
- •1.3. WORK SEQUENCE
- •1.4 APPENDIX
- •1.5 TEST QUESTIONS
- •1.6 REFERENCES
- •2 LABORATORY PRACTICUM: EQUILIBRIUM OF HOMOGENEOUS CHEMICAL SYSTEMS
- •2.1 THEORETICAL INTRODUCTION
- •3.1. THEORETICAL INTRODUCTION
- •2.2. TEST QUESTIONS
- •2.3. REFERENCES
- •Limited Mutual Solubility of Liquids
- •Distribution of the Third Component between Two Immiscible Liquids
- •The used research method is titration.
- •Experiment Procedure
- •The used research method is titration.
- •The used research method is titration.
- •Reagents and materials: a 0.05 M (0.1 N) iodine solution in carbon tetrachloride, a 0.001 M sodium thiosulphate (Na2S2O3) solution, and a 1% freshly prepared aqueous solution of starch.
- •3.2. TEST QUESTIONS
- •3.3. TASKS FOR SELF-STUDY
- •=const,
- •Solution. Let us calculate the K values by the equation,
- •Taking a logarithm of both parts of the expression, one finds that
- •b) The following equation should be used for the case of five consecutive extractions:
- •Problems
- •3.4. REFERENCES
- •4.1. THEORETICAL INTRODUCTION
- •4.2. TEST QUESTIONS
- •LABORATORY EXERCISE 10.
- •4.3. APPENDIX
- •4.4. TEST QUESTIONS
- •4.5 REFERENCES
- •1. Explain the term "molecularity of a chemical reaction". Can the molecularity be greater or smaller than the reaction order?
- •4. Upon studying the kinetics of a chemical reaction, the kinetic curves with different concentrations of reagents have been obtained. Which of the methods of determination of the reaction order is most effective in this case?
- •w = k[HCrO4–][3HSO3–]2[H+].
- •Why is the rate of this reaction not proportional to the number of ions of each sort in accordance with the stoichiometric coefficients in the chemical equation?
- •5.2. KINETICS OF COMPLEX CHEMICAL REACTIONS
- •Task 3
- •5.3. REFERENCES
- •6. INDIVIDUAL ASSIGNMENTS. ELECTROLYTE SOLUTIONS
∆Hhydrat. formation. = ∆Hdissol.anhydr.salt. − ∆Нdissol.hydr.salt. (1.43).
Estimation of Measurement Error
The relative error of the measured thermal constant of a calorimeter Сk is calculated by the equation 44:
∆C |
k |
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2∆(∆Т |
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2∆g |
(1.44). |
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Cк |
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∆Т1 |
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gKCI |
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Different measurements give absolute errors Δ: temperature registration with the naked eye using Beckman thermometer - ∆(∆Т) = ± 0.005°, weighing on a technical weight ∆g = ± 0,02 g. Error of water weight measurement can be regretted because of its small value.
The relative error of a process heat ∆Нis determined by the equation 45:
∆(∆H ) |
= |
∆Ck + |
2∆(∆T ) |
+ |
2∆g |
(1.45), |
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∆H |
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C |
k |
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∆T |
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g |
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where ∆Т is the temperature change during the studied reaction, g is the reactant weight.
Make a conclusion.
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1.4 APPENDIX |
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Table 1.2 |
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Molar Integral Heat of KCl Dissolution |
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Temperature, |
Heat of dissolution, |
Heat of dissolution, J/mole |
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J/mole |
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˚С |
m=0.2 mole/1000 g H2O |
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m=0.1 mole/1000 g H2O |
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25 |
17,550 |
17,570 |
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To determine dissolution heat ∆Hm for КСl solution with this molarity,
the equation 46 is to be used: |
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∆Hm −∆H1 |
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m −m1 |
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(1.46) |
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∆H |
2 |
−∆H |
1 |
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m |
2 |
−m |
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where ∆H1 , ∆H2 are reference values of integral heats of dissolution of salt in water; m1 , m2 are corresponding molarities of solutions.
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Table 1.3
Integral Heats of Dissolution of Studied Salts
(for the molarity of the solution obtained by dissolution of 2 g of salt in 200 ml of Н2О)
Substance |
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NaCl |
KCl |
KNO3 |
KJ |
NiSO4·7H2O |
CuSO4·5H2O |
Na2CO3 |
∆Hm |
, |
4.26 |
17.56 |
34.77 |
20.71 |
17.70 |
10.50 |
-23.7 |
kJ/mole |
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Table 1.4 |
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Specific Heat capacity of KCl Solutions |
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(for the molarity of the solution obtained by dissolution of 2 g of salt in 200 ml of Н2О)
Concentration of |
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Specific Heat Capacity, J/g∙deg |
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solution, |
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mole/1000g |
15 ˚С |
20˚С |
25 ˚С |
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30˚С |
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H2O |
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0.134 |
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4.1600 |
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4.1536 |
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4.1503 |
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4.1471 |
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Specific Heat Capacity of Water |
Table 4 |
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Temperature, |
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15 |
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20 |
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25 |
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30 |
˚С |
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Heat capacity, |
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4.1878 |
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4.1811 |
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4.1786 |
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4.1761 |
J/g∙deg |
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1.5TEST QUESTIONS
1.What is a thermodynamic system?
2.What is a state parameter?
3.What is a state equation?
4.Determine the first law of thermodynamics.
5.Write the mathematical expression for the first law of thermodynamics.
6.What quantities are bonded by the first law of thermodynamics?
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7.What is thermochemistry?
8.What does Kirchhoff's law allow to calculate?
9.What is an essence of Hess’s law?
10.Write the mathematical expression for Kirchhoff's law in differential form.
11.Write the mathematical expression for Kirchhoff's law in integral form with consideration of dependence of reaction heat capacity change on
temperature СР =f(T).
12. Write the mathematical expression for Kirchhoff's law in integral form for case, when heat capacity change does not depend on temperature
( Ср =const).
13. Write the mathematical expression for Kirchhoff's law in integral form for case, when heat capacity does not change during reaction ( Ср =0).
14. Write the mathematical expression for Hess’s law.
15. What is a molar heat capacity?
16. What is a molar specific capacity? What is the dimension of a molar specific capacity?
17. What is a mean heat capacity?
18. Write the mathematical expression for true molar heat capacity? What is the dimension of a true molar heat capacity?
19. Write the mathematical expression for a mean heat capacity. What is the dimension of a mean heat capacity?
20. Give a definition for the heat of a chemical reaction.
21. What is a standard heat of formation ( Н°f,298 )?
22. What substances are elementary substances and complex substances?
23.Give the definition for a standard heat of combustion.
24.Describe reactions and processes which occur during the dissolution of solid salts.
25.Explain why the same heat amount releases under neutralization of any strong acid by any strong base.
26.What is an integral molar heat of dissolution?
27.Which factors influence the value of an integral heat of dissolution?
28.Explain the difference between the first, intermediate and last integral heats of dissolution.
29.What is the difference between an integral dissolution heat and an integral dilution heat?
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30.What is a calorimetric measurements method?
31.What calorimeters do you know?
32.What is the heat capacity (constant) of a calorimeter?
33.How is constant of calorimeter determined?
34.What is the method of a graphical determination of the reaction time and the respective temperature change?
35.What is the method for the determination of the neutralization heat of a strong acid by a strong base?
36.Describe all stages of the experiment for the determination of a salt dissolution heat.
37.What is a sequence to determine the heat of dissociation of weak acids and alkali?
38.Describe all the heats which can be calculated when we determine dissociation heats of weak acids and alkali.
39.How is a heat of crystallohydrate dissolution determined?
1.6REFERENCES
1.Stromberg, A. G.; Semchenko, D. P. Fizicheskaya khimiya [Physical Chemistry], Moscow, High School, 2003. [In Russian]
2.Michshenko, K.P.; Ravdel A.A.; Ponomareva, A.M. (Eds.)
Practicheskie raboty po fizicheskoi khimii [Practicums on Physical Chemistry], Sent-Petersburg, “Professiya” Publ., 2002. 384 p. [In Russian]
3.Ravdel A.A.; Ponomareva, A.M. (Eds.) Kratkiy spravochnik fiziko-khimicheskikh velichin [Quick Reference Book of Physical Chemical
Values], Sent-Petersburg, “Ivan Fedorov” Publ., 2003. 240 p. [In Russian]
4.Gelfman, M.I. (Ed.) Practicum po fizicheskoy khimii [Laboratory Manual on Physical Chemistry], Sent-Petersburg, “Lan” Publ., 2004. 256 p. [In Russian]
5.Selivanova, N.M.; Knayzev, A.A.; Galyametdinov Yu. G. Calorimetricheskie izmereniya teplovikh effektov khimicheskikh reaktsyi i phisikockimicheskikh protsessov [Calorimetric measurements of thermal effects of chemical reactions and physicochemical processes], Kazan, KSTU, 2009.40 p. [In Russian]
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